Seafloor of Red Sea formed at least 12 million years ago

20.09.2016 09:50
Kategorie: News

Discovery overturns present understanding of region’s geological development

Geoscientists find the Red Sea fascinating as it represents an ocean in its early developmental stage. However, due to the difficulty of working in the region, many questions about it remain unanswered. Recent research done by the GEOMAR Helmholtz Centre for Ocean Research Kiel indicates that current concepts about the Red Sea may need to be revised.

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As a fracture emerges along the edges of two tectonic plates, the split gives rise to the formation of new crust which eventually fills up with water. Over millions of years, the rift valley widens, giving rise to a new ocean. This process has taken place many times over the course of the earth’s formation. However, whether the process is the same in every instance remains controversial.

Presently, one of the few regions which has an ocean in its early developmental state is the Red Sea. Researchers from GEOMAR, King Abdulaziz University (KAU) in Jeddah (Saudi Arabia), and Institute of Marine Sciences (ISMAR) in Bologna (Italy) have placed the seafloor of the Red Sea under the microscope to uncover its secrets.

Contrary to previous assumptions, the Red Sea actually resembles a young Atlantic Ocean. Further analyses have confirmed initial results; together with circumstantial evidence, it has been proved that the oceanic crust is millions of years older than previously thought. “The more we evaluate the project data, the more we have to modify existing presumptions about the Red Sea,” said GEOMAR’s Dr Nico Augustin in German. He is the lead author of a paper on the subject, recently published in the Geomorphology journal.

The new findings are the result of three expeditions on the German research vessel Poseidon, the Dutch Pelagia and the Italian Urania in 2005, 2011 and 2012 respectively. Researchers on these expeditions used seabed mapping, sampling and magnetic modelling to examine the rift valley in the central Red Sea.

The researchers discovered structures that were typical of older, slowly spreading ocean basins like the Atlantic or the Arctic Ocean. Such structures include deep transverse valleys, long volcanic ridges and steep faults. The shapes of the underwater volcanoes there are similar to those at older mid-ocean ridges found in the major oceans. “Three large volcanoes – Tethis-Dome, Hatiba Mons and Aswad-Dome – lie directly on the spreading axis in the central Red Sea. This is a typical sign of prolonged and focussed magmatic activity at the rift valleys,” said Dr Froukje van der Zwan, co-author of the study.

Using current geophysical data, the scientists found circumstantial evidence indicating that the oceanic crust in the Red Sea had formed at least 12 million years ago. According to Dr Augustine, this contradicted the present perception that the oldest ocean crust was about five million years old. Despite being obscured by massive sediments, the team’s research also uncovered a much earlier division of the Nubian and Arabian tectonic plates. This would subsequently have implications for the understanding of the region’s geological development.

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